Background signal processing system and background signal processing method

ABSTRACT

A background signal processing method and a background signal processing system are provided. The background signal processing method includes: measuring a first background signal measurement value of a first conductive wire group according to a first background signal measurement value to determine whether a subsequent process is required, and measuring a second background signal measurement value of a second conductive wire group if the subsequent process is required, or ending in this step. A background signal speculating value of a third conductive wire group, other than the first conductive wire group and the second conductive wire group, in the conductive wires is calculated according to the second background signal measurement value and the first background signal measurement value. The background signal processing method greatly simplifies the updating steps for background signals, and ensures quality of the captured signals.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to background signal processingtechnologies, and, more specifically, to a background signal processingmethod and a background signal processing system used in a touch panel.

2. Description of Related Art

It is necessary to filter out the background noise in order toaccurately detect the signal with a touch panel, particularly when usedin capacitance type of touch panel, so as to prevent signal distortion.However, the background noise of the sensor is not constant. As aresult, it is required to frequently detect the background noise andalso update the background noise value, to ensure the quality of signalsthat are to be captured.

However, with the increasing size of the touch panel, the high precisionrequirement and so on, the numbers of sensors used in a touch panel mustincrease, such that the workloads for regularly detecting the backgroundnoise and updating information increase. Further, high frequentlyperforming tasks for updating background noise in a system that isoverloaded can adversely lower the reading frequency, leading to lowperformance for the torch panel, such as an interruption of signal whena continuous touch signal is being detected.

On the contrary, signal distortion may be resulted when the frequency ofupdating background noise is too low, and unaffordable workload forprocessing and updating background noise can adversely affect thereading frequency. Thus, there is an urgent need for developing asolution for reducing the workload of updating background noise as wellas increasing the updating speed, so as to increase the readingfrequency of signals.

SUMMARY OF THE INVENTION

In view of the foregoing prior art problems, the present inventionprovides a background signal processing method and a background signalprocessing system to reduce the burden of updating background noise soas to increase the speed with the quality assured signals beingcaptured, for increasing the reading frequency of the touch penalfrequency.

The present invention provides a background signal processing method,which is used in a sensor device having a plurality of conductive wiresand a predetermined background signal threshold, the background signalprocessing method comprising the following steps of: detecting a firstbackground signal measurement value of a first conductive wire group inthe conductive wires according to a first conductive wire numberinterval, beginning from an n^(th) conductive wire, wherein n is apositive integer; determining whether the first background signalmeasurement value complies with the predetermined background signalthreshold, if yes, stopping in this step, otherwise, detecting a secondbackground signal measurement value of a second conductive wire group inthe conductive wires according to the first conductive wire numberinterval, beginning from an (n+m)^(th) conductive wire, wherein m is apositive integer; and calculating a background signal speculating valueof a third conductive wire group in the conductive wires according tothe first background signal measurement value and the second backgroundsignal measurement value, wherein the third conductive wire group isderived by excluding the first conductive wire group and the secondconductive wire group.

The present invention provides a background signal processing system,which is used in a sensor device having a plurality of conductive wiresand a predetermined background signal threshold, the background signalprocessing system comprising: a storage unit that stores the backgroundsignal threshold; a measurement unit that detects a background signalmeasurement value of the conductive wires; and a determination modulethat determines whether the background signal measurement value complieswith the background signal threshold.

Compared with the conventional technology for measuring the backgroundsignals of all conductive wires, the present invention provides abackground signal processing method and a background signal processingsystem, which are characterized by measuring sections of all conductivewires: the first conductive wire group to obtain the first backgroundsignal measurement value, then determining if a subsequent process isrequired according to first background signal measurement value, if notthe remaining other detection steps can be omitted. This greatlysimplifies the updating steps for background signals and reduces theworkload; if subsequent processes are required, then the secondconductive wire group of all the conductive wires is measured, then thesecond background signal measurement value obtained and first backgroundsignal measurement value obtained prior to that, are used to calculatethe background signal speculating value of the third conductive wiregroup other than the first conductive wire group and the secondconductive wire group in the plurality of conductive wires. Since onlyparts of the conductive wire groups but not all are required to bemeasured, the total workload is reduced and is able to calculate theremaining background signal speculating value of other conductive wiresthat are not measured, thereby capable of providing a completebackground signal to ensure quality signal can be captured.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing the arrangement of conductive wiresapplied to a background signal processing method and a background signalprocessing system according to the present invention;

FIG. 2 is a flow chart of a background signal processing methodaccording to the present invention; and

FIG. 3 is a functional block diagram of a background signal processingsystem according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is described in the following with specificembodiments, so that one skilled in the pertinent art can easilyunderstand other advantages and effects of the present invention fromthe disclosure of the present invention.

FIG. 1 is a schematic view showing the arrangement of conductive wiresapplied to a background signal processing method and a background signalprocessing system according to the present invention.

The background signal processing method according to the presentinvention can be applied in a sensor device having a plurality ofconductive wires, such as a sensor device used in a touch panel. In anembodiment, the arrangement of a plurality of conductive wires can beused in a touch panel with capacitance type of sensor technology. Asshown in FIG. 1, two conductive wire groups each comprise nineconductive wires are arranged in an orthogonal manner. The conductivewires arranged in rows are A₁-A₉, and the conductive wires arranged incolumns are B₁-B₉. Each of the conductive wires can have both drivingand sensing functions.

In an embodiment, the capacitive sensing technology is used to determinethe location of the touch control signal. The method of capacitivesensing can be measuring the self capacitance and mutual capacitancefrom the conductive wires. Take the conductive wires arrangement in FIG.1, when the self capacitance of the conductive wires A₁-A₉ are measured,conductive wires B₁-B₉ are not driven, the sensor function of A₁-A₉ arerespectively used to sensing the self capacitance. On the other hand,when measuring the mutual capacitance, firstly conductive wire A₁, thenconductive wires B₁-B₉ are driven, as well as using the sensor functionof A₁ to sense the mutual capacitance with respect to the conductivewires B₁-B₉, after that, repeat the same steps for conductive wiresA₂-A₉, respectively to obtain the mutual capacitance of the conductivewire A₁-A₉ with respect to the conductive wires B₁-B₉, and so on.Moreover, the background signal processing method and system proposed bythe present invention can be simultaneously used for the measuringmethod for self capacitance and mutual capacitance.

The sensor device may be configured to have a predetermined backgroundsignal threshold. In an embodiment, after the sensor device hasperformed a plurality of (e.g., 10 to 30 times) complete sets ofbackground signal measurement in an isolated electromagneticcompatibility (EMC) environment, a set of background base signal,including the average value and standard deviation of the backgroundsignal, is obtained using a static method, which is used as the basisfor updating the background signal, and according to the background basesignal to determine the background signal threshold, for instance, thethreshold can be the absolute value of the difference of the two (ormore than two) standard value of the background base signals.

FIG. 2 is a flow chart of a background signal processing methodaccording to the present invention. The background signal processingmethod comprises the following steps of:

(S1) detecting a first background signal measurement value of a firstconductive wire group in the conductive wires according to a firstconductive wire number interval, beginning from an n^(th) conductivewire, wherein n is a positive integer;

(S2) determining whether the first background signal measurement valuecomplies with the predetermined background signal threshold, if yes,stopping in this step, otherwise proceeding to step (S3);

(S3) detecting a second background signal measurement value of a secondconductive wire group in the conductive wires according to the firstconductive wire number interval, beginning from an (n+m)^(th) conductivewire, wherein m is a positive integer; and

(S4) calculating a background signal speculating value of a thirdconductive wire group in the conductive wires according to the firstbackground signal measurement value and the second background signalmeasurement value, wherein the third conductive wire group is derived byexcluding the first conductive wire group and the second conductive wiregroup.

In step (S1), n is a positive integer. Referring to FIGS. 1 and 2, takethe configuration that two groups each having 9 conductive wires as anexample. As shown in FIG. 1, when the conductive wires A₁-A₉ aremeasured, n can be made equal to 1, that is from conductive wire A₁, thefirst conductive wire number interval (for example 4) is used to detectconductive wires A₁-A₉, i.e., conductive wires A₁, A₅ and A₉, which arein the first conductive wire group, so as to obtain the first backgroundsignal measurement value.

In step (S2), the first background signal measurement value is to bedetermined whether it complies with the predetermined background signalthreshold, so as to determine the current first background signalmeasurement value and whether the difference between the background basesignals exceeds the predetermined permissible range. In an embodiment,the background signal threshold can be, but is not limited to, theabsolute value of two standard value of the background base signal. Whenthe first background signal measurement value complies with thebackground signal threshold, it is indicated that the absolute value ofthe first background signal measurement value is smaller than thebackground signal threshold. If this condition is met, which means thedifference of the background base signals is still within thepredetermined permissible range, updating is not required, and themethod stops in this step and enters a touch signal detecting mode. Ifthe condition is not met, which means the difference between the basesignals exceeds the predetermined permissible range, step (S3) follows.

In step (S3), m is a positive integer, for example 2. As shown in FIG.1, in the embodiment of n=1, beginning from the (n+m)^(th) conductivewire, i.e., from conductive wire A₃, the first conductive wire numberinterval (for instance 4) is used to detect conductive wires A₁-A₉,i.e., conductive wires A₃ and A₇, which are in the second conductivewire group, so as to obtain the second background signal measurementvalue.

In step (S4), according to the first background signal measurement valuemeasured from conductive wires A₁, A₅ and A₉, and the second backgroundsignal measurement value measured from conductive wires A₃ and A₇, thebackground signal speculating value of the conductive wires A₂, A₄, A₆and A₈ in the third conductive wire group outside of the A₁, A₅ and A₉in the first conductive wire group and the A₃ and A₇ in the secondconductive wire group can be obtained.

In the background signal processing method according to the presentinvention, the background signal measurement value and the speculatingvalue of conductive wires A₁-A₉ can be obtained, which can be used as abasis to filter out the noise during the touch signal capturing process,so as to ensure quality touch signals being captured. Compared with theprior art, which measures all the conductive wires, the backgroundsignal processing method provided by the present invention only measuressome of the conductive wires. For instance, only conductive wires A₁,A₃, A₅, A₇ and A₉ are measured, as compared to all conductive wires inthe prior art. In other words, only 5/9 of the conductive wires aremeasured, thereby greatly reducing the workload for updating thebackground noise, as well as increasing the updating speed.

In an embodiment, the background signal processing method according tothe present invention further comprises step (S5) of updating all of thebackground signals of the sensor device according to the firstbackground signal measurement value, the second background signalmeasurement value and the background signal speculating value of thethird conductive wire group as the new basis. Then, a touch signaldetecting mode can be entered.

In step (S4) of an embodiment, the background signal speculating valueof the third conductive wire group is calculated by an interpolationmethod, such as Lagrange interpolation, Spline interpolation or otherinterpolation methods. Take the aforementioned embodiment of measuringof the conductive wires A₁-A₉ as an example, the background signalmeasurement value of the conductive wires A₁ and A₃ are used tocalculate the background signal speculating value of conductive wire A₂using an linear interpolation method; or use the background signalmeasurement value of conductive wire A₃ and A₅, to calculate thebackground signal speculating value of conductive wire A₄ using linearinterpolation method, and so on.

FIG. 3 is a functional block diagram of a background signal processingsystem 1 according to the present invention. The background signalprocessing system 1 can be applied in a sensor device having a pluralityof conductive wires. The sensor device comprises a predeterminedbackground signal threshold. The background signal processing system 1comprises a storage unit 10, a measurement unit 11 and a determinationmodule 12, and a processing unit 13 or a calculation module 14,optionally.

The storage unit 10 is used to store the background signal threshold,which is determined by the background base signal.

The measurement unit 11 is used to detect the background signalmeasurement value of the conductive wires.

The determination module 12 is used to determine whether the backgroundsignal measurement value complies with the background signal threshold.In an embodiment, the background signal threshold can be the absolutevalue of two standard difference value of the background base signal.When the background signal measurement value complies with thethreshold, it is indicated that the absolute value of the backgroundsignal measurement value is smaller than the threshold.

In an embodiment, the determination module 12 further generatesbackground signal updating instructions when the background signalmeasurement value does not comply with the background signal threshold,indicating that the difference between the background signal measurementvalue and the background base signals exceeds the predeterminedpermissible range. The background signal processing system 1 canoptionally includes a processing unit 13 that updates the backgroundsignals after receiving the background signal updating information.

In an embodiment, the background signal processing system 1 can beapplied in a sensor device having a plurality of conductive wiresarranged in an orthogonal manner, as shown in FIG. 1.

In an embodiment, the measurement unit 11 can be used to detect thefirst background signal measurement value of the first conductive wiregroup in the conductive wires, beginning from the n^(th) conductivewire, according to the first conductive wire number interval. Thedetermination module 12 is used to determine whether the firstbackground signal measurement value complies with the predeterminedbackground signal threshold, wherein n is a positive integer.

The measurement unit 11 can be used to, when the first background signalmeasurement value does not comply with the predetermined backgroundsignal threshold, detect the second background signal measurement valueof the second conductive wire group, beginning from the (n+m)^(th)conductive wire, in the plurality of conductive wires according to thefirst conductive wire number interval, wherein m is a positive integer.

In an embodiment, the background signal processing system 1 canoptionally includes a calculation module 14, which is used to calculatethe background signal speculating value of the third conductive wiregroup, other than the first conductive wire group and the secondconductive wire group, in the conductive wires according to the firstbackground signal measurement value and the second background signalmeasurement value. Since the background signal measurement value or thebackground signal speculating value are obtained for all the conductivewires, the noise can be filtered out during the process of capturing thetouch signals, for ensuring that the signals to be captured have highprecision and high quality.

In an embodiment, the calculation module 14 is used to calculate thebackground signal of the third conductive wire group by an interpolationmethod, such as Lagrange interpolation, Spline interpolation or otherinterpolation method, so as to obtain the background signal speculatingvalue.

In summary, the background signal processing method and the backgroundsignal processing system according to the present invention arecharacterized by measuring sections of all conductive wires: the firstconductive wire group to obtain the first background signal measurementvalue, then determining if a subsequent process is required according tofirst background signal measurement value, if not the remaining otherdetection steps can be omitted. This greatly simplifies the updatingsteps for background signals and reduces the workload; if subsequentprocesses are required, then the second conductive wire group of all theconductive wires is measured, then the second background signalmeasurement value obtained and first background signal measurement valueobtained prior to that, are used to calculate the background signalspeculating value of the third conductive wire group other than thefirst conductive wire group and the second conductive wire group in theplurality of conductive wires. Since only parts of the conductive wiregroups but not all are required to be measured, the total workload isreduced and is able to calculate the remaining background signalspeculating value of other conductive wires that are not measured,thereby capable of providing a complete background signal to ensurequality signal can be captured.

The present invention has been described using exemplary preferredembodiments. However, it is to be understood that the scope of thepresent invention is not limited to the disclosed embodiments. On thecontrary, it is intended to cover various modifications and similararrangements. The scope of the claims, therefore, should be accorded thebroadest interpretation so as to encompass all such modifications andsimilar arrangements.

What is claimed is:
 1. A background signal processing method, which isused in a sensor device having a plurality of conductive wires and apredetermined background signal threshold, the background signalprocessing method comprising the following steps of: (1) detecting afirst background signal measurement value of a first conductive wiregroup in the conductive wires according to a first conductive wirenumber interval, beginning from an n^(th) conductive wire, wherein n isa positive integer; (2) determining whether the first background signalmeasurement value complies with the predetermined background signalthreshold, if yes, stopping in this step, otherwise, proceeding to step(3); (3) detecting a second background signal measurement value of asecond conductive wire group in the conductive wires according to thefirst conductive wire number interval, beginning from an (n+m)^(th)conductive wire, wherein m is a positive integer; and (4) calculating abackground signal speculating value of a third conductive wire group inthe conductive wires according to the first background signalmeasurement value and the second background signal measurement value,wherein the third conductive wire group is derived by excluding thefirst conductive wire group and the second conductive wire group.
 2. Thebackground signal processing method of claim 1, further comprising thestep of: (5) updating a background signal of the sensor device accordingto the first background signal measurement value, the second backgroundsignal measurement value and the background signal speculating value. 3.The background signal processing method of claim 1, wherein theconductive wires are arranged in an orthogonal manner.
 4. The backgroundsignal processing method of claim 1, wherein in step (4) the backgroundsignal speculating value of the third conductive wire group iscalculated by an interpolation method.
 5. A background signal processingsystem, which is used in a sensor device having a plurality ofconductive wires and a predetermined background signal threshold, thebackground signal processing system comprising: a storage unit thatstores the background signal threshold; a measurement unit that detectsa background signal measurement value of the conductive wires; and adetermination module that determines whether the background signalmeasurement value complies with the background signal threshold, whereinthe measurement unit detects a first background signal measurement valueof a first conductive wire group in the conductive wires, beginning froman n^(th) conductive wire, according to a first conductive wire numberinterval, and the determination module determines whether the firstbackground signal measurement value complies with the predeterminedbackground signal threshold, wherein n is a positive integer, themeasurement unit further detects a second background signal measurementvalue of a second conductive wire group in the conductive wires,beginning from an (n+m)^(th) conductive wire according to the firstconductive wire number interval when the first background signalmeasurement value does not comply with the predetermined backgroundsignal threshold, wherein m is a positive integer, and the backgroundsignal processing system further comprises a calculation module thatcalculates a background signal speculating value of the third conductivewire group, other than the first conductive wire group and the secondconductive wire group, in the conductive wires according to the firstbackground signal measurement value and the second background signalmeasurement value.
 6. The background signal processing system of claim5, wherein the determination module further generates background signalupdating instructions when the background signal measurement value doesnot comply with the background signal threshold, and the backgroundsignal processing system further comprises: a processing unit thatupdates a background signal of the sensor device after receiving thebackground signal updating information.
 7. The background signalprocessing system of claim 5, wherein the conductive wires are arrangedin an orthogonal manner.
 8. The background signal processing system ofclaim 5, wherein the calculation module calculates a background signalof the third conductive wire group using an interpolation method, so asto obtain the background signal speculating value.